CNN News: 火山噴發(fā)

 
More than 80 percent of the Earths surface above and below sea level is volcanic and deep below the Earth's tectonic plates are always moving. 

超過80%的地球表面以上以及海平面以下是火山活動范圍，而在地球構造板塊深處總是在移動。

Most volcanic activity occurs where these plates collide. Deep within the Earth it is so hot that rocks slowly melt and become magma. Because this flowing substance is lighter than the rocks around it, it rises. When some of these tectonic plates shift, the magma rises even higher. Some of the magma pushes through the cracks in the Earth's crust at vent and at fissures and reaches the surface where it is then called lava. 
 
大多數(shù)火山活動發(fā)生在板塊碰撞的地方。在地球深處，溫度很高，以至于巖石慢慢地融化成為巖漿。因為這種流動的物質(zhì)比它周圍的巖石輕，所以會上升。當這些構造板塊移動時，巖漿會上升得更高。一些巖漿從火山口和裂縫處穿過地殼的裂縫，到達地表，在那里它被稱為熔巖。

What kind of eruption a volcano will have depends on the properties of the magma. Thin and runny magma means gas trying to escape can do so easily. 

火山噴發(fā)的類型取決于巖漿的性質(zhì)。稀薄的巖漿意味著氣體很容易逃逸。

When this happens the lava will flow out of the volcano. We've seen this with Hawaii's volcanoes because the lava flows slowly people can get away quickly and it rarely results in victims. But thick and sticky magma is a different story. There's less room for gases to escape and the pressure mounts.
 
當這種情況發(fā)生時，熔巖就會從火山中流出。我們在夏威夷的火山上看到過這種情況，因為熔巖流緩慢，人們可以迅速逃離，很少有人受傷。但粘稠的巖漿則是另一回事。因為氣體逸出的空間更小，壓力也更大。
 
Gas gets trapped in the magma which then explodes at the surface. This is called an explosive eruption and we've seen it with Mount Etna in Sicily and Mount Saint Helens in the U.S. 
 
氣體被困在巖漿中，然后發(fā)生地表爆炸，這被稱為爆發(fā)性噴發(fā)，我們在西西里島的埃特納火山和美國的圣海倫斯火山都見過。

Explosive volcanic eruptions can be dangerous and deadly. Lava, ash, debris can destroy everything in their path. In some cases, these eruptions have buried entire communities like Mount Vesuvius in Pompeii and Mount Pelee in Martinique. About 500 volcanoes have erupted since we started keeping records.
 
爆炸性的火山噴發(fā)可能是危險致命的。熔巖、火山灰和碎片會摧毀所經(jīng)之處一切事物。在某些情況下，這些火山爆發(fā)掩埋了整個社區(qū)，比如龐貝的維蘇威火山和馬提尼克的佩利火山。自從我們開始記錄以來，大約有500座火山爆發(fā)。
 
Many around the "Ring of Fire", an area from New Zealand to the coast of South America where there are the most subduction zones and plate movements. All volcanic activity is closely monitored by scientists around the world. By tracking active volcanoes, experts can see the warning signs and alert the public before an eruption. 
 
在“火圈”周圍，從新西蘭到南美洲海岸，是俯沖帶和板塊運動最多的地區(qū)。全世界的科學家都在密切監(jiān)視著所有的火山活動。通過追蹤活火山，專家們可以看到火山爆發(fā)前的警告信號并向公眾發(fā)出警報。